The invention relates to new compounds that can be used by themselves or in mixtures as detergent additive compositions for fuels.
It is known that automobile engines have a tendency to form deposits on the surface of the engine elements, in particular on the carburetor orifices, the bodies of butterfly valves, fuel injectors, cylinder orifices and intake valves, because of oxidation and polymerization of various hydrocarbon-containing components of the fuel. These deposits, even when they are present only in small amounts, are often responsible for significant driving problems, such as the engine timing and poor acceleration. In addition, deposits in the engine can significantly increase the consumption of fuel and the production of pollutants. This is why the development of effective detergent additives for regulating these deposits assumes a considerable importance and was already the object of much research.
A new family of compounds that exhibit good effectiveness as additives that are intended to reduce the deposits in the injectors and in the intake valves has now been discovered.
The compounds of the invention can be defined by the following general formula (I): 
in which n is a number from 0 to 20, preferably 0 to 10; R1, R2, R3, and R4 each represent a hydrogen atom or a hydrocarbon radical, for example alkyl, with 1 to 30 carbon atoms, whereby at least one of R1, R2, R3, and R4 is a hydrocarbon radical; and whereby the concatenations: 
can consist of patterns: 
that differ from one another by the nature of R1, R2, R3 and/or R4; and m is a number from 1 to 30.
The compounds of the invention generally come in the form of mixtures of compounds that differ from one another by the value of n, and/or by the nature of at least one of radicals R1 to R4. It is then a matter of compositions.
The synthesis of the compounds or compositions defined above can be carried out as described below. It generally comprises the reaction of a hydroxymethylated derivative of tetrahydrofuran with ethylene oxide, then with one or more other epoxidized compounds.
The hydroxymethylated derivative of tetrahydrofuran, such as, for example, 2-(hydroxymethyl) tetrahydrofuran, is mixed with, for example, sodium hydride. After having purged, under stirring, the reactor of the released hydrogen, the ethylene oxide is optionally introduced in an amount that is calculated to obtain the desired value of n, and the medium is brought to a temperature of 60 to 130xc2x0 C., then epoxide or a mixture of epoxides of general formula 
in which R1, R2, R3 and R4 are defined as above, is added at an amount that is calculated to obtain the desired value of m, and the medium is brought to a temperature of 80 to 180xc2x0 C., and the reaction mixture is kept at this temperature until the end of the consumption of the epoxide or epoxides.
After returning to ambient temperature, the medium is diluted with an organic solvent, for example a hydrocarbon solvent, such as heptane, it is washed with water one or more times, then, after evaporation under reduced pressure of the organic phase, the product that corresponds to general formula (I) is obtained: 
The compositions of the invention can be used as detergent additives in the gasoline-type fuels. In this application, they can be added to the fuels at concentrations of, for example, 20 to 5000 mg per liter. They can also be used mixed with any other detergent compound.